What the FDA labels say about taking them together
Disopyramide and flecainide
Disopyramide's FDA label of August 24, 2026 names flecainide in its boxed warning section; the flecainide label PlainMeds reads does not name disopyramide.
Check it at the source: the disopyramide FDA label on DailyMed (effective August 24, 2026, Pfizer Laboratories Div Pfizer Inc); the flecainide FDA label on DailyMed (effective June 11, 2026, Amneal Pharmaceuticals of New York LLC).
What does the disopyramide label say about flecainide?
Disopyramide label, boxed warningMortality In the National Heart, Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multi-center, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had had a myocardial infarction more than 6 days but less than 2 years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%).
Disopyramide label, warningsConcomitant Antiarrhythmic Therapy The concomitant use of Norpace or Norpace CR with other Type 1A antiarrhythmic agents (such as quinidine or procainamide), Type 1C antiarrhythmics (such as encainide, flecainide or propafenone), and/or propranolol should be reserved for patients with life-threatening arrhythmias who are demonstrably unresponsive to single-agent antiarrhythmic therapy.
Source: FDA drug label (Norpace), Pfizer Laboratories Div Pfizer Inc, effective August 24, 2026 (SPL set e2aa1642-d262-4520-bc6a-9fd3ad795677), via openFDA; the full label on DailyMed
What does the flecainide label say about disopyramide?
Flecainide's label (effective June 11, 2026) does not name disopyramide in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Flecainide Acetate), Amneal Pharmaceuticals of New York LLC, effective June 11, 2026 (SPL set ee9595d5-08a1-4529-9215-ddc3c7f929c4), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Disopyramide | Flecainide | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.801 per capsule 100 mg capsule | $0.171 per tablet 100 mg tablet |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once